1. Field of Invention
The present invention relates to a piezoelectric ceramic composition and piezoelectric elements, and more particular, to a piezoelectric element composed of plural ceramic layers to form a positive and a negative electrode conductive circuits and a piezoelectric actuator, loudspeaker or buzzer using the piezoelectric element.
2. Related Art
The piezoelectric actuator, loudspeaker or buzzer typically uses a piezoelectric element to be stimulated by driving signals received from positive and negative electrodes to produce sound.
The conventional piezoelectric element includes a ceramic sheet of single layer attached on one surface of a metal plate. Each ceramic sheet has exposed surface coated with a conductive material as an electrode layer for a conducting line from a positive electrode of a signal provider to be soldered thereon. A negative electrode of the signal provider is soldered on the metal board. As such, the driving signals can be transmitted from outside to stimulate the piezoelectric element to resonate and the piezoelectric element can be used for the piezoelectric actuator, loudspeaker or buzzer to produce sound.
However, due to single layer of ceramic sheet is attached on the metal plate; therefore, higher driving voltage is required to obtain better output sound. If the signal provider inputs lower voltage signal, it is hard to obtain good resonant sound between the single ceramic sheet and the metal plate. This is an issue needed to be overcome.